Control mechanism



Feb. 19,-1952 R. PRATT 2,586,085

CONTROL MECHANISM QT-ro RA/Ers.

Feb. 19, 1952 R, PRATT 2,586,085

CONTROL MECHANVISM Filed March 20, 1948 4 Sheets-Sheet 3 t' f: ,272 5e U ik 227 ,5y/,5g 242546 25a 225 3 2?/ 246 59 f4 ,270 60 /4/ 230 A m 238 l" .ff/2 26a 235 /55 5 @y 203 ga 64 251 M s l 256 24%' /60 /57 224 172 "6 272 '5g 47 55 9 73 /a u mi iz /56 24o V f /0 ,68 M6 f 2' 220 272 2?/ l "E" 2 VME X y 249 374 258 23a 233 zo,

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Feb. 19, 1952 R, PRATT CONTROL MECHANISM 4 Sheets-'Sheerl 4 Filed March 20, 1948 Patented Feb. 19, 1952 UNITED STATI-1S ore-r1 ce oroN'raoL MEoHANIsM Ryder Prat`t,`Kv-irkrivood, to Missouri Automatic Controlv Corporation; StiLous, MU.,

.ai-corporation of`-l\ `iss0uri'^ i f Appicatitn March zo, 1924s, serial No. 15,981

The present invention relates generally to a contr01 device infwhich a' heat-generating-ap paratus is automatically controlled in' response to la demand for heat within algivenfspacep Further, "thelinventionpertains generally to a receptacle for centaining the relays`,switchesiand J when the cover is taken'off'. i 2 f More particularly, the invention is directed to the switch mechanism and the'novel manner in which it is mounted on the panel in relation to and in combinationl With the other elements fthereonf@ In applicants pending application, Serial No. 605,863, iiled July 19, 1945, -novv Patent No.' 2,486,- 612,V there 'is'described in detail a control circuit v'of i the typereierred to above That circuitis schematically illustrated, and provides av system f particularly adaptable tol controlling the action of an oil burner. l

The principal object of this invention is to provide a novel compact package unithaving in convenient arrangement a set ofcontrol elements employed in connection with a burner, and especially an oil burner. Specically, it is-an object to provide a novel support or base unit of insulating material Whereon the ignition switch, .'r, the Warp switch, the ysafety warp switch, ,the l safety and scavenger heaters, and the scavenger warp switch of a vburner control system may be mounted; means whereby the support may be readily attached to or removed from the removable panel of a wall receptacle; and meansassociated with the cover for said receptacle whereby the safety warp switch of said system may be manually reset without removal of the cover.

It is a further object of the invention to rprovide a support and combination of elements-'that are compact in design, so that all` theabove specied elements of the control system are assembled in a group, whereby adjustments errepairs, if required, may be made quickly-and-easily.

Another object of the invention .is to provide means on the casing of the receptacle, in cooperation with means on the panel, whereby lthe latter may be readily positioned -on or removed from-the receptacle; means on -the panelv for n mounting the transformer and the relays of said system successively adjacent` the switch mechanism support, and means whereby thecover for the receptacle may be maintained in place.v nulrraddition to those enumerated, other objects and advantages lof the invention will'becom'e apparent or hnoted in the description to follow, reference being had alsoto theaccompany'ing drawings which. illustrate the preferred form of the invention., In said drawings l' Y l Fig.A 1 .is airont elevational view of a receptacle incorporating the 'present invention, the receptacle being portrayed in" position on a' fragmentary portion of a Wall orthe like,-and in connec- .tion with-thed combustion orstack switch of the systern'yth'estack being in vertical' section; .,Fig. 2 is an end elevational View ofthe receptacle asit appearsfrom the right in Fig. 1, the wall 0n which itA is mounted being shown in secfFig. 3 is a front elevational view of the receptacle and its contents with the cover thereof in vertical section; -Figi isfa yvertical sectional view taken approximately on the line ll--4v ofFig. 1, the view beingiindica-tedfalsofby the line 4 4 of Figi' 3; f1:Fig:isalfragmentary sectional view taken on ,i 1g."` 6 'sl an' enlarged left side elevation of a unitary switchassembly comprising'fthe principal eoin'ponent'of "the'present invention', theV assemblybingillustrated as it appearswhen' removed nomtherceptaciey 1' A e Fig.y 7 is asimilar right side elevational view thereon: Y Y Y A l Fig. 8 is a top plan view thereof; `Fig-9 isa-vertical sectional view thereof, taken approximately online 9:-9 of Fig. 8 ;4

" Fign'lfis asimilarview talrenapproximately on 11inefv lil-"lil of4 Fig. r3; adjacent portions'ofa Vpanel-onI which' the assembly lisl'mounted being lomittedy f ygsiT 11, 12 and 13 are horizontal sectional views thereof taken-approximatelyfon lines Ii- *II, Al2--Il2 and I3Li3offlig'. 8, adjacent Vportions of :Said nanerbeingdmitted;

J'Fig "1134 'is affra'gmentary view of a manual reset means;v` the view'being incit-atec` by une :ef-n c .cFigAad l, l

Hl'igiv 15 is a diagram substantially incorporatigthe' circuit; diagramv of said pending application, in addition to schematically embodying other elements included inthe present invention.

Description of the control cycle With particular reference now to Fig. 15, the control circuit will be briefly described, employing the same reference characters that are employed in the previously mentioned copending application to designate the similar parts. The mode of operation will not be described except where it is thought necessary to understand the invention.

Thus, in Fig. 15, as in the drawings on file, there is shown a primary branch having two lines II and I2, connected to a suitable source of power and feeding an ignition device I3, and a burner motor device I4 through a relay switch mechanism I5. Electric current to the ignition devices is supplied by the lines II, 2I, I6, the left-hand switch of the relay switch mechanism I5, the line I1, the ignition switch 24, the line I8, the igniter I3, and lines I9 and I2. The circuit for the burner motor includes the lines II and 2l, the right-hand switch of the relay I5, the line 22, the burner motor I4 and the lines 23, I9 and I2.

The relay switch I5 is illustrated as having tw-o separate switch elements, of which one is connected into the igniter circuit and the other into the burner motor circuit. Both switches are simultaneously operated to closed or open positions by the energization and deenergization of the coils, as will appear, and for immediate purposes may be considered functionally as one switch.

The two switch elements mentioned comprise two relatively xed contacts 25 and 26 that are respectively engaged by two movable contacts 21 and 28 when the coil'mechanism, generally indicated at 3|, is energized in the manner to appear. The coil mechanism 3l is in a low voltage circuit that is energized from a transformer 34, having a primary winding 35 connected by wires 36 across the power lines II and I2, and a secondary 31.

The low voltage circuit includes several control elements. There is a space thermostat 32, preferably having an anticipating heater 33. There is a combustion switch 5I, having a main contact 53, a cold side contact 54 and a hot side contact 6I. This control has heat-responsive elements a that are subjected to heat of combustion of the burner. In the absence of combustion, the contact 53 is closed with the contact 54. In the presence of combustion, the contact 53 moves over to contact with the contact 6I. In moving from the cold to the hot side, the contact 53 makes with the contact 6I before it breaks with the contact 54.

There are the main relay coil 46 and the secondary relay coil 66. The main relay coil is of adequate power to operate both switches I5 from open to closed positions. The secondary coil 66 adds suflicient impedance, when connected in series with the main coil, to reduce the strength of the two coils to between that required to pull the switches closed and that minimum power to hold them closed.

Other control elements include a safety warp switch and a scavenger warp switch. The safety warp switch is generally indicated at 48. The details of this switch will appear later. Suce it at present to say that it includes a heater 56 that acts upon a thermally-responsive switch element, such as a bimetal, to open switch contacts.

The scavenger warp switch also is a heat relay type of switch having a scavenger heater 63 that acts upon a heat-responsive element such as the bimetal strip to operate switch contacts. Both the safety warp switch 48 and the scavenger warp switch 58 are opened when their respective heaters attain predetermined temperature values.

The low voltage or secondary circuits for the operation of the relay switch mechanism I5 may be considered as under primary regulation of the room thermostat 32. It will be seen that the secondary 31 of the transformer 34 is connected by a line 42 to the anticipating heater 33 of the room thermostat, which heater 33 is, in turn, connected by a wire 4I to the room thermostat. The room thermostat has a switch blade 15 that is capable of closing with the contact 16. The contact 16 is connected by a line 44 to a terminal R. From this terminal R, a line 59 leads up to the scavenger warp switch 58, the details of which switch will be discussed hereafter. However, the blade of this switch is connected by a wire 51 through the safety heater 56 of the safety warp switch. This heater, in turn, is connected by a wire 55 that leads through a terminal E and reaches the cold contact 54 of the combustion switch 5I. The main or center contact 53 of the combustion switch is connected by a line 52 that leads through a terminal F and goes to the safety warp switch. The other side of the safety warp switch is connected by a wire 41 that leads to the main relay coil 46. The other end of this coil is connected by a wire 45 through a terminal 38 and a wire 43 to the other side of the secondary 31,

The wire 59 that leads from the contact 16 of the room thermostat 32, by way oi the line 44 and the terminal R, is as already noted connected into the scavenger warp switch 58. It is also connected, as indicated, directly into the scavenger heater 63 of the scavenger warp switch. The other end of this switch is connected by a wire 64 that is connected also to a wire 65. The wire 65 leads to one end of the secondary relay coil 66. The other end of the relay coil 66 is connected by a wire 62 through a terminal L to the hot contact 6I of the combustion switch 5I.

Without going into an extended discussion of the cycle of operation of the over-al1 control, it may be stated briefly that, when the room thermostat 32 becomes excessively cold, it closes the blade 15 against the contact 16. This establishes a circuit from the constantly energized secondary 31 through the wire 42, the anticipating heater 33, the wire 4I, the thermostat 32, the wires 44 and 59, the scavenger warp switch, the wire 51, the safety heater 56, the wire 55, the cold side contact 54, the main contact 53 of the combustion switch, the wire 52, the safety warp switch, the wire 41, the main relay coil 45, the wire 45 and the wire 43 back to the secondary. As the combustion switch is on the cold side at the start of any operation, the foregoing circuit can be closed, and the main relay coil 46 energized. When the main relay coil is energized, the Switch I5 is closed, whereupon the circuits to the burner motor I4 and igniter I3 are closed by the previously described circuits. Thus, as soon as the room thermostat closes, the burner motor and the igniter begin to operate.

Also, on the low voltage side, the closure of the room thermostat 32 establishes a circuit that energizes the safety heater 56, which begins to heat up and thereby begins a condition that, if continued, would cause the safety warp switch to open, breaking the previously mentioned cirlarly, the offset rear wall I 1 has formed thereon a lateral projection |3| anda vertical projection |32.

Obviously, the arrangement whereby insertion of the projections |29 and |32 into the slots |01 and |08, followed by the swinging of the assembly rearwardly until the lateral projections |28 and |3| engage the notches |09 and ||0, provides an adequate support for the said assembly.

Since the wall I |1 is rearwardly offset relative the wall H6, the forward edge of the wall 81, in which the notch is formed, lies relatively close to the back wall 82. The offset in the panel is provided to more adequately accommodate the relay assembly 3| and its associated switch mechanism I5. This entire assembly is secured to the panel by means of screws |34. The housing of the transformer 34 is similarly attached by screws |36. Insertion and removal of the panel assembly is facilitated by the provision of an arcuate recess |31 centrally along the top of the panel.

For a purpose to be explained, a rectangular opening |38 is formed in the forward wall ||6 of the panel, and an ear |39, provided with a threaded aperture, extends laterally into the opening, as shown particularly in Fig. 5.

The member I2 I, which, as previously described, is attached to the depending extension I I9 of said panel, extends longitudinally across the recepta- :u

cle from the left end wall 86 to the right end wall 81.

The member |2| serves as a mounting plate for a series of terminals, by means of which the external wiring is connected to the wiring inside :5,

the receptacle.

The terminal posts on the plate |2I, reading from right to left, are designated A, B, C, D, E, F, L, T and R. The wires entering the receptacle via the openings ||2, and the terminal posts to which they are attached, appear clearly in Fig. 3.

The leads from the opposite side of the plate |2| to the various elements on the panel are wires 2| and 36 from terminal A, wire 38 from ter minal B, a continuation of wire 22 from C, a i

continuation of wire I8 from D, wire 55 from E, wire 52 from F, a continuation of wire 92 from L, a continuation of wire 42 from T, and wire 59 from terminal R.

As earlier indicated, the composite switch assembly, shown per se in Figs. 6 through 13, comprises a principal component of the invention. This assembly, generally designated |40, includes a molded support or base |4| of plastic material,

the configuration of which is clearly illustrated.

It is seen to include a generally rectangular body portion I 43, provided on either side with a laterally projecting flange portion |45. There is also a rearwardly projecting L-shaped ilange portion |46 which may be seen to best advantage in Fig. 5. The lower forward edge of the body |43 is notched or cut out, as at |48, and, as shown particularly in Fig. 12, a horizontally disposed aperture |49 is formed adjacent the left margin thereof.

With this arrangement, the assembly may be manually inserted or removed from the opening |38 of the panel wall |IG. When in place, with the fianges |45 against the front face of said wall, and the vertical portion of the notch |48 against the rear face thereof, a screw |52 is passed through the aperture |49 into engage ment with the aperture in the ear |39. t should, therefore, be obvious that, whereas fortuitous displacement of said assembly is obviated, its removal from the panel, ii' desired, is a very simple operation.

Reverting now to the support |4|, it is noted that, projecting beyond the rear face of its body portion |43, there are seven terminal elements, designated |55, |56, |51, |58, |59, |60 and |6|. Each of these terminals is permanently secured, by means of either rivets or screws |63, to the body |43, which, as shown, is either recessed or slotted, or both, as the case may be, to accommodate the base and body portions of said terminals. From an inspection particularly of Fig. 5, it is seen that the lead I1 terminates at and is soldered to the terminal |55, the lead 52 r to the terminal |56, and the lead 41 to the terminal |51. To the terminal |58 is soldered one end of the wire |8. to the terminal |59 the ends of wires 55, to the terminal |50 the ends of wires 59, and to the terminal the ends of the leads 94 and 65. also indicated in Fig. 15, so that the elements of the assembly |40, served by the various wires enumerated, should be readily apparent.

The novel construction whereby the switch and heater elements of the assembly |40 are operatively mounted in compact relationship to one another on the support |48 will now be described. With respect to the ignition switch 24, which includes a contact |65 (Figs. 4, 6, '1, 11) at one end of a blade |66, the support is provided with a forwardly projecting boss portion |98, within a groove |69 of which said blade lies, its other end being fastened by one of the rivets |53 to the terminal |55. This arrangement is especially portrayed in Fig. 1l.

The ignition switch 24 further includes a contact |12 at the upper end of an angularly contoured blade |13 (Fig. 6), the lower end of which is riveted, as at |14, to a forwardly and then laterally extending portion |15 of the terminal |58. This arrangement is especially portrayed in Figs. 3, 6, 9 and 10.

With respect to the safety warp switch 48, which includes a contact |18 adjacent the lower channel-shaped end |19 of a blade |80, the body |43 is provided with a recess |82 to receive the upper end |83 of said blade. A rivet |63, passing therethrough, through a rigid vertical retaining strip |84, and through the support, connects the blade with the terminal |51.

This construction is seen to best advantage in Figs. 4 and '7, wherein it is also seen that the lower end |19 of the blade terminates in a forwardly extending substantially horizontal portion |85, to which is attached, by rivets |86, a fibrous or other non-conductive member |88, in contact with the button |00 of the reset device.

I The switch 4S also includes a contact |90, normally closed with the contact |18, and carried by the free end of a blade |92 secured by rivets |93 to the laterally projecting ilange |94 of an auxiliary blade |95.

As shown particularly in Fig. 12, the blade |95 is secured to a forwardly projecting boss portion |98 of the support, by means of the screw |63 which also secures the terminal |56 thereto. The boss portion |98 is formed immediately below the boss |68, as shown. Said terminal |56 includes an oifset downwardly extending portion 200, which carries an adjustment screw 20|', normally biasing the blade |95 slightly to the left, as seen in Fig. 3. Attention is also directed to Fig. 7 in this connection.

Reverting again to Fig. 12, and considering also Figs. 3 and 10, a screw 203 entering the boss |98, on the side opposite the'blade |95, secures to the The terminals |55 through |6| are vstrip 201, another pad of insulation 2D8', and

nally a non-conductive strip 209.

To the lower end of the bimetal strip 285 is riveted a depending strip 2 |2 of brous material,

. which normally overlies the tip 2|3 of the blade |52, to bias the latter rearwardly, as shown in Fig. 13. This view also shows a resilient abutment pad 2|5 for the blade-|85 secured to the support by the screw |63, with which the terminal |S| is fastened to the support.

Wound about the strip 201 is the Winding 2|6 of the safety heater 55, connected at one end to the lead 55 and at the other to the wire 51. band of insulation 2|8 is interposed between the strip 209 and the extension |15 of the*r terminal |58.

A pivotal mounting for the scavenger war-p switch mechanism 58 is also provided on the support. Included are a pair of apertured bosses 22u and 22|, which project rearwardly and receive the ends of a pivot pin 222. The assembled scavenger switch is of generally U-shaped oo nfiguration in end elevation, and 'includes a base f.;

member 224. provided with a pair of spaced'upstanding apertured ears 225, through which the pin 222 extends. The member 224 is also provided with a pair of upstanding extensions 226 land 228, as best seen in Fig. 6.

To the forward extension 226, there is attached, by rivets 229, a further upwardly. extending blade 230, the upper end of which carries a contact 232 and an angularly contoured member 233. a magnet 235,as shown in Fig. 11. The magnet normally biases the blade 23B rearwardly to bring the contact 232 into engagement with a contact 23B on the upper end of a blade 231 secured to an extension 238 of the terminal |60.

Also attached to said support, by a rivet 239, and extending therefrom laterally to the left, is an abutment strip 240 for the member 233 when it moves forwardly to disengage the contacts 232 and 236 under conditions set forth in the copending application.

The blade 23e also carries a right-angular iibrous element 245, the horizontal portion 246 of which extends through a vertical slot 248 in the blade |13, and the upstanding portion 249 of which is in engagement with the front face of said blade. The horizontal portion 246 of said member is rigidly attached to a depending flange of the element 233 bv a rivet 25|.

To the rearward upstanding extension 228 of the scavenger switch base member 224, there is attached, by rivets 25o, a further upwardly extending strip 253 of bimetal, the upper end of which is bifurcated as at 259, and a pliant strip of insulation 260.

rihe strip 255B is provided with a pair of spaced terminals 252 and 263, to which are soldered or otherwise permanently attached the ends of the Scavenger heater winding 265, which is coiled about a non-conductive wrapper 261 surrounding the strip 258.

As may be seen by referring to Figs. 9 and l1, a threaded stud 21E, embedded in a rearwardly projecting boss 2'il of the support, extends through the bifurcation 259. An abutrrent in the form of a nut or the like 212 is aixed to the projecting end of the stud 210, whereby movement of the strip 252 is limited in a rearward direction. A manually rotatable nut `214 is Embedded inthe supportV 4| is l0 provided to limit themo'vement of said strip in a forward direction.

Obviously, this arrangement provides a ready adjustment for regulating the operational movements of the scavenger warp switch in accordance with the requirements of the copending burner control system.

In View of the foregoing, it should be manifest that the objectives of the invention are attained. A compact assembly is provided in the form of a receptacle which contains not only a number of conventional'elernents associated with the burner control systemof the character under consideration, but'which additionally includes novel supporting means for those mechanisms vwhich are 'most critical in the'su'ccessful operation of said System.

- 'The advantages inherent in the unitary support whereon said criticalniechanisms are mounted, and -the facilities provided whereby said support may be quickly installed or removed from the panel of the receptacle, should also be apparent.

It is, of course, understood that, in a mechanism of the type illustrated, structural modications may be made by those skilled in this art without departing from the spirit of the invention. Therefore, the scope of this invention'is to be limited only by the claims.

Whatris claimed is:

l. In combination, a base, a pair of power terminals on the base, a first set of a pair of accessory terminals on the base, a second set of three accessory terminals on the base; a main relay coil on the base, an armature displaced by energization of the coil, an electrical power reducing means on the base for the relay coil adapted to reduce the power of the main coil to below that required to displace vthe armature but above that required to hold the armature once it is displaced by the main coil; a safety relay on the base, of the time delay type, having a switch and an energizing means energizable to open the relay switch; a scavenger relay on the base cf the timedelay type having a switch'and an energizing means energizable to open the switch; first circuit branch connections connecting in series the power terminals, the first accessory terminals, the scavenger relay switch, the safety relay energizing means, a first and second of the three second accessory terminals, the safety relay switch, and the main relay coil; second circuit branch connections connecting in series the power terminals, the first accessory terminals, the scavenger relay energizing means, the newer reducing means, the second and third of the seco'frl accessory terminals of which one is not common to the first circuit branch, the safety relay switch, and the main relay coil; the first circuit branch energizing the safety relay energizing means tn open the safety relay switch after a predetermined time, but the energization second circuit branch being exclusive of said energizing means whereby unless the second branch .is energized and the first is deenergized, the safety switch will open to prevent energization of either circuit branch.

2. The combination of claim 1 in which the safety relay switch, once opened, remains open upon subsequent deenergization of the energizing,

means therefor, and means to reclose the same.

3. The combination of claim 1, together with an additional switch connected to be operated concurrently with operation of the scavenger relay switch.

4, In combination, a base, a safety relay on the base, of the time delay type, comprising a relay switch and an operating means therefor; a scavenger relay on the base, of the time delay type, having a relay switch and operating means therefor, one side of the scavenger relay switch being connected with one side of the scavenger relay operating means, the other side of the said relay switch being connected to one side of the safety relay energizing means; a terminal connected with the said one side of the scavenger relay switch, having means for mounting an external connection thereto; a terminal connected with the other side of the safety relay energizing means, having means for mounting an external connection thereto; a terminal connected with the other side of the scavenger relay operating means, having means for mounting an external connection thereto; a terminal on the other side of the safety relay switch, having means for mounting an external connection thereto: the safety switch being of the nonself-closing type, and means for reclosing the safety switch after deenergization of its operating means.

5. The combination of claim 4, together with an additional switch connected to be operated concurrently with the `scavenger relay switch, and terminals for said additional switch.

6. In a switch mechanism: a base; a safety switch on the base, comprising a relay having a heater and a heat-responsive relay switch; a scavenger relay on the base having a heater and a heat-responsive relay switch, the scavenger relay switch including a U-shaped member pivoted to the base, with its heater and a heatresponsive leg lying on one side of the base, and the other leg, having switch contact means, lying 12 along the other side of the base, the safety switch heater and heat-responsive means being on said other side to minimize heat transfer from one heater to the other heat-responsive means; a connection between the scavenger relay switch and the safety heater to put them in series; and means connecting the scavenger heater with one 4side of the scavenger relay switch.

7. The combination of claim 6, with`an additional switch mounted on the base adjacent the scavenger relay switch, and a member connecting the two switches for conjoint operation.

RYDER PRATI'.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS NumberV Name Date 885,061 Lee Apr. 21, 1908 1,010,414 Cubitt Dec. 5, 1911 1,491,278 Siebert Apr. 22, 1924 1,744,209 Burnett Jan. 21, 1930 1,801,303 Brand Apr. 21, 1931 2,150,012 Von Hoorn Mar. 7, 1939 2,195,761 Wheelock Apr. 2, 1940 2,217,488 Mahnke Oct. 8, 1940 2,314,225 Leece Mar. 16, 1943 2,362,304' Reed Nov. 7, 1944 2,439,326 Wilson Apr. 6, 1948 2,446,029 Tramontini July 27, 1948 2,491,987 Lefcourt Dec. 20, 1949 FOREIGN PATENTS Number Country lDate 488,478 Great Britain July 7, 1938 636,945 France Apr. 19, 1928 

